How to open asynchronous IO on HP's host

Asynchronous
First, talk about asynchronous IO (Aio)
In HP-UX, when synchronous IO is used, this means that the previous IO must return the "successful write" information before the next write Io, and see a performance bottleneck in the synchronous IO mode in a system with a larger IO load. In the case of asynchronous IO, the operating system immediately returns to the application a successful message after the write request is sent, and the rest is done by the operating system. When using Oracle, Sybase these databases in HP-UX, to reduce IO bottlenecks and improve library performance, it is recommended that opening asynchronous IO,HP is relatively cumbersome in this regard relative to Aix.

Second, HP-UX aspects to open AIO need to do the setup
1, HP-UX use of AIO patch requirements
The patch requirements for a, HP-UX 11.00 are:
phkl_22126:s700_800 Vm,async,hyperfabric
b, the patch requirements for HP-UX 11i are:
phkl_25212 vm preemption Point, Mlock/async_io
phkl_25506 Asyncio Driver Patch
Use the Swlist-l product to check for patches on the Wuru, such as if you didn't contact HP's supporter to hit it.
2, the creation of AIO character equipment
A, the establishment of AIO character equipment
#/sbin/mknod/dev/async C 0x0
b, to adjust the owner of the device, this example assumes the user is Oracle, the group is DBA
#chown Oracle:dba/dev/async
C, adjust the device's permission bit
#chmod 660/dev/async
3. HP-UX kernel parameters to be adjusted
Adjusting kernel parameter data requires the root user to be used
A, put the Asyncdsk in
sam-> Kernel Configuration-> Drivers->asyncdsk adjusted to In
B, adjust the max_async_ports parameters
This parameter is limited to the maximum number of processes using the/dev/async device at the same time, and for Oracle This parameter should be greater than or equal to the number of processes in the processes+ background in Init<sid>.ora, and for Sybase it identifies the maximum number of worker processes. When the value of Max_async_ports is reached, the rest of the process will take the form of synchronous IO.
C, adjust set aio_max_ops parameters
This parameter is defined as the maximum number of AIO operations queued at any one point in time, and the default value is generally maintained, which can be monitored with glance.
D, adjust the Fs_async parameters
This parameter indicates whether the file system is written in Aio, set fs_async=0 Specify the file system to write without AIO, set the fs_async=1 to specify the way to use AIO, Oracle does not recommend this set to 1
4, other aspects of Setup
The most important point is that you must set Mlock permissions for the group of Oracle users (typically DBA), otherwise, if the database startup will be an error or the library will run a baffling database hang phenomenon, I simply say.
A, involving two commands getprivgrp what permissions are used for the inspection Unit, SETPRIVGRP is used to set permissions for the group, for example, you'll see.
EG1: Check whether the DBA group has Mlock permissions
ROOT#GETPRIVGRP DBA
EG2: Set the Mlock permissions for the DBA group
ROOLT#SETPRIVGRP DBA Mlock
b, you can also add the settings to the configuration file, so that the next time the startup will automatically take effect.
Add the following line to the/etc/privgroup:
DBA Mlock
If Privgroup does not exist, you can edit one.

Third, the database use AIO to do the setup
1, Oracle Side
A. 7.3.0 previous version: No need to configure parameters in Init<sid>.ora
B. 7.3.X: Set use_async_io = TRUE in Init<sid>.ora
C. 8.X and later versions: Set disk_asynch_io = TRUE in Init<sid>.ora
2, Sybase aspects
The default is to open AIO.

Four, other
1. Check if AIO is in effect
#fuser/dev/async
There are processes listed to show that AIO is in effect.
2, my hp11.00+oracle8.1.6.0.0 environment to enable AIO sometimes will appear bad block problem (ora-01578), please note, but in the hp11i system and oracle8i,9i with the cooperation did not appear this problem.